1. Field of the Invention
This invention relates to circuit breakers and hot wire relays for use in protecting a circuit from high leakage current or short circuits.
2. Description of the Prior Art
The present invention relates to a time delay disconnect switch or hot wire relay as one component of a ground fault circuit interrupter for use with an appliance such as an electric range to remove power for the purpose of preventing high current leakage hazards or short circuit damage. Such ground fault circuit interrupters (GFCI) are required by the Underwriters Laboratory, Inc., for use in bathrooms, with outdoor residential receptacles, swimming pools and the like.
The present invention is combined with a disconnect switch in the form of a hot wire relay of a special design to obtain time delay, as is described in the above-cited pending application. An example of a simple hot wire relay is shown in the Bergsma Patent No. 3,176,099 which uses an in-circuit self-heating resistance wire referred to as a "hot" wire or "sag" wire such that when the magnitude of the input current exceeds a certain limit the hot wire will elongate sufficiently for making or breaking the output circuit-controlling electrical contact.
Another example of a snap-action hot wire power-switching relay is described in the Staples U.S. Pat. No. 3,514,733, which is assigned to the assignee of the present invention. One of the main differences between the disconnect switch of the present invention and the Staples relay is the construction to provide time delay in the present disconnect switch to avoid spurious operation and distructive arcing and premature failure.
The Doyle U.S. Pat. No. 3,864,649 shows a ground fault circuit interrupter and its disconnect switch combined in a single wiring device, while in the present invention the disconnect switch is separate from the sensing and firing circuit.
The present disconnect switch employs wiping contact action which serves to maintain the contact surfaces clean, but this is not generally new, per se, as is depicted in the Sway U.S. Pat. No. 2,671,840 and the Hottenroth U.S. Pat. No. 2,350,960, both of which are assigned to the present assignee. It is felt that the present invention relates to a manual reset mechanism which can be operated from a remote position. This reset mechanism is such that it prevents the operator from holding the disconnect contacts closed while a fault is present in the circuit.
The principal object of the present invention is to provide a disconnect switch for use in a ground fault circuit interrupter system with a manual reset mechanism which may be operated from a remote position, but which is disabled whenever a fault is present in any circuit so as to prevent the operator from being able to hold the disconnect contacts closed.
A further object of the present invention is to provide a reset mechanism for a disconnect switch which cooperates with a latching mechanism for an actuator plunger that, when released by the latching mechanism, serves to open the switch contacts.
A further object of the present invention is to provide a reset mechanism of the class described which is carried by the latching mechanism and is movable with respect thereto for being able to cock the actuator plunger after the ground fault has been corrected.